1. Field of the Invention
The present invention relates to an organic light emitting diode display device having improved light extraction efficiency and display quality.
2. Discussion of the Related Art
Image display devices, which display a variety of information on a screen, are a core technology of information and communication and are becoming increasingly thinner, lighter, more portable and higher performance. Due to pursuit of extended lifespan and convenience, flexible displays are required and thereby organic light emitting diode display devices controlling the light emitting amount of an organic emission layer are receiving attention recently.
Organic light emitting diode display devices include a first electrode, an organic light emission layer and a second electrode sequentially laminated between an upper substrate and a lower substrate. In organic light emitting display devices, an electric field is formed in a first electrode and a second electrode in both end portions of an organic light emission layer and thereby an electroluminescence phenomenon occurring due to energy release upon recombination of electrons and holes by injecting the electrons and the holes into an organic light emission layer, and transferring the electrons and the holes to the organic light emission layer is used.
The organic light emitting diode display device as described above does not require a separate light source unlike liquid crystal displays. Therefore, the organic light emitting diodes are light weight, and have a thin thickness. In addition, the organic light emitting diodes have high quality characteristics such as low power consumption, high luminance, high reaction rate and the like, and thereby are receiving attention as a next generation display device of portable electronic devices. Recently, to improve light extraction efficiency of the organic light emitting diode display devices, a light extraction pattern is further provided.
FIG. 1 is a sectional view of a general organic light emitting diode display device, and FIGS. 2A and 2B are images illustrating defects in a general organic light emitting diode display device.
As illustrated in FIG. 1, the general organic light emitting diode display device further includes a light extraction pattern 30 on a substrate 10 in which light generated from an organic light emitting cell of each sub-pixel 20 is emitted to the outside. Additionally, light generated from the organic light emitting cells affects a neighboring sub-pixel 20 through the light extraction pattern 30. For example, even in an area corresponding to an OFF sub-pixel, an image is displayed by a neighboring ON sub-pixel and, as such, defects such as a blur, ghost image and the like occur as illustrated in FIGS. 2A and 2B.